element plus中动态form-item

对应动态生成的el-form-item 增加校验规则。改用行内定义，具体方法如：

<el-form-item :prop="xx"   :rules="{required: true, message: 'Please input Activity name', trigger: 'blur'}">....</el-form-item>

官网demo

element-plus.org/zh-CN/compo…

<template>
  <el-form
    ref="formRef"
    style="max-width: 600px"
    :model="dynamicValidateForm"
    label-width="auto"
    class="demo-dynamic"
  >
    <el-form-item
      prop="email"
      label="Email"
      :rules="[
        {
          required: true,
          message: 'Please input email address',
          trigger: 'blur',
        },
        {
          type: 'email',
          message: 'Please input correct email address',
          trigger: ['blur', 'change'],
        },
      ]"
    >
      <el-input v-model="dynamicValidateForm.email" />
    </el-form-item>
    <el-form-item
      v-for="(domain, index) in dynamicValidateForm.domains"
      :key="domain.key"
      :label="'Domain' + index"
      :prop="'domains.' + index + '.value'"
      :rules="{
        required: true,
        message: 'domain can not be null',
        trigger: 'blur',
      }"
    >
      <el-input v-model="domain.value" />
      <el-button class="mt-2" @click.prevent="removeDomain(domain)">
        Delete
      </el-button>
    </el-form-item>
    <el-form-item>
      <el-button type="primary" @click="submitForm(formRef)">Submit</el-button>
      <el-button @click="addDomain">New domain</el-button>
      <el-button @click="resetForm(formRef)">Reset</el-button>
    </el-form-item>
  </el-form>
</template>

<script lang="ts" setup>
import { reactive, ref } from 'vue'
import type { FormInstance } from 'element-plus'

const formRef = ref<FormInstance>()
const dynamicValidateForm = reactive<{
  domains: DomainItem[]
  email: string
}>({
  domains: [
    {
      key: 1,
      value: '',
    },
  ],
  email: '',
})

interface DomainItem {
  key: number
  value: string
}

const removeDomain = (item: DomainItem) => {
  const index = dynamicValidateForm.domains.indexOf(item)
  if (index !== -1) {
    dynamicValidateForm.domains.splice(index, 1)
  }
}

const addDomain = () => {
  dynamicValidateForm.domains.push({
    key: Date.now(),
    value: '',
  })
}

const submitForm = (formEl: FormInstance | undefined) => {
  if (!formEl) return
  formEl.validate((valid) => {
    if (valid) {
      console.log('submit!')
    } else {
      console.log('error submit!')
    }
  })
}

const resetForm = (formEl: FormInstance | undefined) => {
  if (!formEl) return
  formEl.resetFields()
}
</script>

动态form-item增加校验

这里可能会有疑问，为什么不能像那样用v-for迭代过程中的变量，如上代码中的item来写:prop="item.name"。v-for及迭代变量item是渲染界面时用的。渲染完，item就不存在，不能访问了。而我们的校验是在渲染完后才启用的。必须保证后面阶段也能访问到对应数据。index渲染完也是不可访问的。只是上面的写法相当于把index当时的值固化下来了，是后面也能访问到。用的是字符串拼接来引用index，相当于闭包的作用。只要符合这样的机制，访问路径即便更复杂，比如双重迭代。也是可以使用自带校验的。

<el-form :model="arry">
        <template v-for="(item,index) in arry" :key="index">
                <el-form-item :prop="'arry['+index+'].name'" :rules="{required: true,message: '名称还未填写',trigger: 'blur'}">
                    <el-input v-model="item.name">
                </el-form-item>
        </template>

const arry=ref([{name:'a'},{name:'b'}])